Depression is characterized by persistent feelings of sadness or hopelessness.  Depression can feel like a heavy weight that drags a person down and makes it difficult to carry out daily activities. It often manifests as a lack of interest in things that a person previously enjoyed or a persistent feeling of emptiness. Symptoms can also include difficulty sleeping, changes in appetite or weight, fatigue, feelings of worthlessness or guilt, and difficulty concentrating. Depression can impact a person's relationships, work productivity and self-esteem.